Packet-switched networks such as those that utilize the Internet protocol are essential tools of many of today's businesses. Hence, it is essential that these networks be monitored to ensure the network traffic encounters minimal delays and other problems during transport. Such monitoring, however, involves the collection and storage of significant amounts of data. This presents several challenges, among them the problem of how to ensure data is collected for at least a minimum number of network nodes of a number of logical groups of such nodes at each of several time scales.